Is Your Horse's Water Bucket Half Full or Half Empty?

Is Your Horse's Water Bucket Half Full or Half Empty?

Researchers developed a test to find out whether horses are optimistic, pessimistic, or somewhere in between.


After a training session, your horse goes back to his resting area and looks in his water bucket for a drink. The water level is at the halfway mark. So, does your horse think his bucket is half full or half empty?

Yes, even horses can be optimistic or pessimistic, according to Swiss equine behavior scientists who have developed a test to find out whether horses are one or the other, or somewhere in between. In fact, the researchers recently used the test to determine how positive and negative reinforcement affect horses’ outlook: Does it put them in an optimistic or pessimistic mood?

They found that while negative reinforcement fosters more negative emotions, the horses actually become more optimistic once negative reinforcement training ends than with positive reinforcement—at least in this particular study, said Sabrina Briefer Freymond, MSc, a researcher at Agroscope-Swiss National Stud in Avenches.

“Animal welfare is commonly linked to physical state and mental state,” said Briefer Freymond. “And because animals cannot tell us how they feel, it’s really important—and it’s a real challenge—to measure emotions.” Briefer Freymond presented her work at the 9th Conference of the International Society for Equitation Science (ISES), held July 17-19 at the University of Delaware in Newark.

In her experiment, Briefer Freymond and her fellow researchers used a novel method—called the “judgment bias approach”—to test horses’ level of optimism. Scientists have used judgment bias tests successfully with other species, but never before with horses.

The team first trained 12 mares in a paddock to find a lidded bucket placed in one of two locations several yards apart. If the bucket was placed on the left side, it contained food. If it was placed on the right, it was empty. All the mares quickly learned that there was no point in lifting the lid off the bucket on the right side of the paddock because it was sure to be empty.

Once this level of optimism had been achieved, the researchers trained the horses various tasks using either positive or negative reinforcement. With positive reinforcement, horses are trained to perform a task and rewarded, usually via food, upon completing the desired action. With negative reinforcement, horses are given an unpleasant stimulus—such as pressure from a hand, leg, or whip—until they perform the desired action; the unpleasant stimulus is then removed immediately. During the training process the researchers observed the horses’ behavior (body position, attitude toward the trainer, and ear position) and monitored their physiological parameters (heart rate variability, skin temperature, and respiration rate). This training process lasted five days.

Once the training was completed, the mares began the second phase of the optimism experiment. In this phase the team placed an additional bucket at a location between the original two. They established three different locations where they might set the bucket between the “reward” spot and the “empty” spot. Their theory was similar to the “glass half full or glass half empty” concept: If the horses were willing to check for food in the in-between locations, they were considered to be more optimistic than those who wouldn’t try at all.

The researchers observed the horses to determine which ones hoped for food in the buckets (the optimistic ones) and which did not (the pessimistic ones). The researchers noted that during the training period the mares in the positive reinforcement group showed more positive behavior signs than those in the negative reinforcement group. This suggested that the mares in the positive reinforcement group experienced more positive emotions than those in the negative reinforcement group, Briefer Freymond said.

However (and unexpectedly, said Briefer Freymond), the mares in the negative reinforcement group showed more optimism than the mares in the positive group in phase two of the optimism test, “despite experiencing negative emotions during the (training),” said Briefer Freymond.

“This was really contrary to our hypothesis,” she said. “It could be that since the negative reinforcement group wasn’t rewarded during the training part, these horses were more motivated during the (optimism) test. But it could also be that the end of the negative reinforcement training does, in fact, make horses more optimistic.”

Similar studies have shown that after intense stress sheep are actually more optimistic than those that have not recently undergone intense stress, she said.

“However, this could also be a phenomenon unique to mares,” Briefer Freymond added. “Prior research has shown that it is characteristic of females (of other species) after short- or long-term stress to develop an optimistic bias, but this does not seem to be the case for males.”

Further studies using optimism tests might be more reliable if food is not used in the test, she said; a social reward (finding other horses) could be a good replacement for food in a similar test. The Swiss National Stud group’s research is ongoing.

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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